What's the cause of a dog's belly turning black?

There are several possible reasons for a dog's belly turning black:

Hyperpigmentation: Factors such as aging, UV radiation, and damaged skin follicles can lead to melanin deposition in the skin, causing darkening.
Skin diseases: bacterial or fungal infections can cause moss-like symptoms on the skin.
Endocrine disorders: such as hypothyroidism, hypoparathyroidism, and estrogen excess, can lead to skin pigmentation.
Dirt: If a dog spends a lot of time on the ground and doesn't have regular baths, dirt can accumulate on its belly.
Hyperpigmentation

The aging process, UV radiation, and damaged skin follicles can cause melanin to accumulate in the skin, leading to skin pigmentation. This is a normal physiological phenomenon and there is no need to worry too much.

Skin diseases

Skin diseases caused by bacterial or fungal infections in dogs can also lead to moss-like symptoms on the skin. At the same time, dogs may also experience itching, redness, swelling, and hair loss. If these symptoms are found, it is necessary to go to the pet hospital promptly for examination and diagnosis, and then treat accordingly.

Endocrine disorders

The dog's belly turning black may also be caused by endocrine disorders, such as hypothyroidism, hypoparathyroidism, and estrogen excess, which lead to skin pigmentation. Symmetrical hair loss may also occur. It is necessary to take the dog to the pet hospital for identification and diagnosis, and then treat accordingly.

Dirt

If the owner doesn't give the dog a bath for a long time, the dog will rub against the ground, leading to the accumulation of dirt on its belly, making it look dark. In this case, just regularly bathe and dry the dog, keeping it clean.